The present invention relates to the field of V configuration double overhead cam shaft internal combustion engines, and in particular to a configuration for such a V configuration double overhead cam shaft engine in which the number of different parts required is reduced.
Generally, a V type double overhead cam shaft engine is provided with a left cylinder band and a right cylinder bank; when the engine is of V6 configuration, there are three cylinders in each of said right and said left bank, while, when the engine is of V8 configuration, there are four cylinders in each of said right and said left bank. The left cylinder bank has a left intake cam shaft and a left exhaust cam shaft (since the engine is particularly of the double overhead cam shaft type), while similarly the right cylinder bank has a right intake cam shaft and a right exhaust cam shaft; thus, in all, four cam shafts are provided to the engine, two intake and two exhaust. And each of the right and left cylinder banks has its set of intake valves and its set of exhaust valves, and these are respectively controlled with regard to their opening and closing by the intake and the exhaust cam shaft for said cylinder bank.
Now, although such V type double overhead cam shaft engines have conspicuous advantages in terms of performance, which make them particularly suitable for modern automobiles, they suffer from the disadvantage that they require a comparatively large number of parts, as compared with straight or in line type internal combustion engines, such as for example straight six engines. This proliferation of parts is particularly problematical in the valve gear of such V type double overhead cam shaft engines. Further, the number of different types of parts utilized in a V type double overhead cam shaft engine in the prior art tended to be much greater than in a straight type engine, and this gives problems with regard to convenience of manufacture of such an engine, loss of economies of scale, and stocking of spare parts.
In particular, such a V type double overhead cam shaft engine has in the past required its four cam shafts to be manufactured as individual parts, each differently made from the other three. Thus, four different types of cam shaft have been required to be manufactured for making the V type double overhead cam shaft engine, and this has been a serious problem in view of cost and inconvenience during manufacture and assembly. And, as suggested above, during operation of this V type double overhead cam shaft engine, service depots have been required to stock four different kinds of cam shaft for said engine, which is troublesome, burdensome, a likely cause or error, and expensive from the stocking point of view.